What causes a mesh to look like swiss cheese

[JonVarner]

I am currently working on a project and was testing it on an iphone 6 and noticed that part of the geometry looks like Swiss cheese. Any ideas on what might be causing this?

This is an example of what it looks on the iphone:

 

This is what it looks like on the desktop:

 

[SvenFrankson]

Is the binder animated with bones ? If so maybe it's because of limitations about the "bones per vertex" number ? I think it's low for mobiles (documentation says 3 on mobile, 4 on desktop https://doc.babylonjs.com/how_to/how_to_use_bones_and_skeletons )

[JonVarner]

Thanks Sven, all of my vertices had 4 influences. So I decided to prune them to 3 per vertex and sure enough the problem was gone. Thanks for your help.

[SvenFrankson]

Have you tried checking the real value of numBoneInfluencers on your mesh ?

For example, add in your loading method, where myAnimatedBinder is your animated mesh.

alert(myAnimatedBinder.numBoneInfluencers)

(debugging mobile like a boss, but note that alternative and more sophisticated methods involve a properly setup Safari browser and a USB-Iphone cable...)

If it says less than 4, some bone influences might be dropped, causing the holes...

[JonVarner]

Thanks, yeah after trimming them all to 3 per vertex everything looked correct. You were spot on.